1. Technical Field
The present invention relates to a developing device of an output apparatus using an electrophotography processor and, more specifically, to a method and arrangement for separately retrieving used developing material on a developing roller and supplying new developing material while balancing the retrieval of the used developing material with the supply of the new developing material in accordance with an increase in the number of papers being printed.
2. Related Art
Typically, a cleanerless developing system has a supply roller connected to a developing roller for performing the retrieval of used toner, as well as supply and friction-charging of the new toner. In such systems, the functions of retrieving used toner, supplying new toner and friction-charging the toner are simultaneously performed.
However, in such a system, there is a problem in that it is difficult to properly set the level of the power supply which supplies power to the supply roller of such a system, the supply roller being made of semiconductive elastic sponge. Furthermore, such systems have a limited design in that they cannot achieve a balance between the supply of the toner and retrieval of the toner while varying the resistance of the roller in accordance with an increase in the number of papers being printed. As a result, such systems are incapable of obtaining a stable image.
Therefore, there is a need for the development of a method for retrieving/supplying developing material in an electrophotography forming apparatus, and in particular, there is a need to provide a method for separately retrieving used developing material on a developing roller and supplying new developing material, while at the same time balancing the retrieval of the used developing material with the supplying of a new developing material in accordance with an increase in the number of pages or papers being printed.
The following patents are considered to be representative of the prior art relative to the present invention, and are burdened by the disadvantage discussed above: U.S. Pat. No. 5,729,267 to Shimada et al., entitled Image Forming Apparatus Having Image Transfer With Toner Cleaning Function, U.S. Pat. No. 5,726,695 to Ueda, entitled Developing Device, U.S. Pat. No. 5,717,981 to Yamanaka, entitled Developing Device For Electrophotographic Image Forming Apparatus, U.S. Pat. No. 5,678,143 to Nagahara et al., entitled Image Forming Apparatus For Collecting Residual Toner From A Drum Using An AC Voltage, U.S. Pat. No. 5,671,465 to Kimura et al., entitled Image Forming Apparatus Having A Revolver Type Developing Device, U.S. Pat. No. 5,526,099 to Katakabe, entitled Developing Device And An Image Forming Apparatus Using The Same, U.S. Pat. No. 5,473,417 to Hirano, entitled Developing Apparatus Having Toner Supply Roller Applied With Bias Voltage Varied In Accordance With Changes In Physical Properties Thereof, U.S. Pat. No. 5,420,668 to Okano, entitled Image Forming Apparatus, U.S. Pat. No. 5,333,040 to Imamiya, entitled Developing Device Having Improved Toner Transport Capacity For Use In An Image Forming Apparatus, U.S. Pat. No. 5,032,872 to Folkins et al., entitled Developing Device With Dual Donor Rollers Including Electrically Biased Electrodes For Each Donor Roller, U.S. Pat. No. 4,947,212 to Ikegawa et al, entitled Developing Apparatus With Color Dependent Toner Supply Voltage, U.S. Pat. No. 4,912,513 to Oka et al., entitled Developing Apparatus With Variable Developing Bias Voltage, U.S. Pat. No. 4,714,942 to Nakanishi, entitled Reversal Image Development Type Electrophotographic Printing System, U.S. Pat. No. 4,878,088 to Nakanishi entitled Developing Unit Of Electrophotographic Apparatus, U.S. Pat. No. 4,811,686 to Yamane, entitled Developing Device Of An Electrophotographic Machine, U.S. Pat. No. 4,545,669 to Hays et al., entitled Low Voltage Electrophotography With Simultaneous Photoreceptor Charging, Exposure And Development, U.S. Pat. No. 4,522,481 to Imai et al., entitled Toner Supply Control Method For Electrophotographic Copier, U.S. Pat. No. 4,480,911 to Itaya et al., entitled Developing Apparatus And A Developing Method Of An Electrostatic Image, and U.S. Pat. No. 4,277,003 to Tabuchi et al., entitled Developing Material Supplying Device.